Molding composition comprising polyvinyl chloride or polyethylene and a metal oxide



Unitedfiews P m MOLDING COMPOSITION COMPRISING POLY- 4 'VINYL CHLORIDE R POLYETHYLENE AND -A METAL OXIDE Y Harry Kloepfer, Frankfurt am Main, Germany, assignor I to. Deutsche Goldund Silber-Scheideanstalt vormals Roessler, Frankfurt am Main, Germany --No Drawing. Application May 20, 1955, Serial No.

510,011. In Germany December 31, 1948 Public Law 619, August 23, 1954 Patent expires December 31, 1968 The presentinvention relates to improvements in the production ofmoulded bodies, consisting wholly or in part of natural or synthetic rubber or rubber-like or synthetic resin-like substances or mixtures thereof together with finely divided oxides..

According to the invention it has been found that the properties of the moulded bodies can be considerably improved in various respects, for example with regard to hardness, elasticity, extension, abrasion-resistance, impact resistance and the like by making use of highly dispersed oxides of metal or metalloids which have been produced by the thermal decomposition of volatile compounds of metals or, metalloids in the vapour state by means of oxidising or hydrolysing agents, if desired in the presence of a gaseous or vaporous diluent or of combustible" gases. i Accordingly the present invention provides a process for the production of moulded bodies consisting wholly or partially of natural or synthetic rubber or of rubberlike or synthetic resin-like substances or mixtures thereof together with finely divided oxides, including the step of incorporating with the materials to be moulded oxides which have been produced by the thermal decomposition of volatile compounds of metals or metalloids in the vapour state by means of oxidising or hydrolysing agents, if desired in the presence of a gaseous or vaporous diluent or of combustible gases.

The present invention also provides a moulding composition and moulded products comprising natural or synthetic rubber or "rubber-like-or synthetic resin-like substances or mixtures thereof, together with finely divided oxides which have'been produced by thermal decomposition of volatile compounds of metals or metalloids in the vapour state by means of oxidising or hydrolysing agents, ifdesired in the presence of a gaseous or vaporous diluent or combustible gases. The term high molecular weight" polymeric material is used hereinafter to mean the above-mentioned natural or synthetic rubber or rubher-like materialsor synthetic resin-like substances or mixtures thereof. I

Suitable compounds of metals or metalloids from which highly dispersed oxides may beproduced include for example ferric chloride, aluminum chloride, titanium tetrachloride, beryllium chloride, beryllium acetate,

2,874,140 Patented Feb. 1.7, .1959

tageously be carried out in the presence of a furth gaseous or vaporous diluent, such for example as nitrogen, carbon dioxide, hydrogen and the like, whereby the respective metal oxides are obtained as a particularly fine dispersion, for example as aerosols which are collected as aerogels.

Working in the presence of large quantities of these diluents has the advantage that an undesired increase in particle size is prevented and moreover undesired rises in temperature (for example oxidation) can be rendered innocuous.

The essential factor in the productionof the oxides em.- ployed according to the invention is that they are produced in a vapour phase reaction in which a volatilised metal or metalloid compound is reacted to form an oxide aerosol which agglomerates to form an-aerogel, usually upon cooling, which is then collected by cyclones, filters or upon cooled moving surfaces, preferably, however, at a temperature above the dew point of the easily condensable by-products of the reaction, such as, hydrochloric acid and water vapour. Preferably, the volatile compounds from which the highly'dispersed oxides are produced are the halides of, such as, for example, silicon tetrachloride, aluminum chloride, titanium tetrachloride and the like. Such volatile halides can, for example be introduced into a flame in the presence of air ,or other oxygen containing gas and if desired in the presence. of a combustible gas containing freeor combined hydrogen, for example, hydrogen, hydrocarbon gases and illuminat: ing gas. It is not essential to employ a flame for the reaction. For example, the volatile compounds, such as, silicon tetrachloride, titanium tetrachloride or aluminum chloride, can be reacted in the vapour phase with water vapour and/or air at an elevated temperature, for example 250 to 300 C., to give the desired highly dispersed oxides.

The oxide aerogels employed according to the invention have an exceedingly fine elementary particle size, for example, below 0.05 1. and preferably below 0.01,u. These elementary particles are weakly agglomerated in the aerogels and are redispersed upon thorough mixing with the high molecular weight polymeric materials.

The .finely divided aerogels can be employed in the production of moulded bodies which consist wholly or resins, such for example as polyisobutylene, co-polymers chromyl chloride, vanadyl chloride Or especially silicon bonyl,'z inc dimethyl, magnesium dimethyl and the like may be reacted with oxygen'or air, if desired at moderatel y raised: temperatures, whereby the respective metal oxides are formed I in colloidal dispersion.

. l 'ljhe hydrolyses. oroxidations described can advanthereof with vinyl acetate and the like or polymeric viny'l, acryl compounds, vinyl acetate, vinyl-chloride, styrene, or acrylic acid esters, polyethylene, polyamide resins and polyester resins. The said synthetic resins can be subjected to polymerisation before or after addition of the said colloidal metal oxides. It is frequently advantageous to incorporate the active filler with the aid of rollers, if desired friction rollers. Alternatively the polymerised compounds, for example, polymethacrylic acid esters mixed with monomeric methacrylic acid esters canbe mixedwith polymerisation catalysts, such for example as benzoyl peroxide, and the aerogels, and the polymerisation can then be completed. Instead of using catalysts,

. 1 polymerisation can also be efiected'in manner known per se by irradiation with short wave-length light.

By using synthetic resin-like substances or substances which give synthetic resin-like masses, moulded bodies are obtained which are distinguished by particularly great hardness, impact-resistance and .thelike. The present in- I 3 I vention' can be applied with advantage to the production of synthetic resin teeth, prostheses and other dental aids. Since the strengthening action is very strong even with small additions it is possible according to the present invention to produce bodies of a transparency which is only slightly reduced.

It is already known to add finely divided or colloidal metal oxides to synthetic resin masses of the phenolformaldehyde type, such as those sold under the registered trademark Bakelite.

It was found, however, that particularly favourable results are only obtained when aerogels are used accordto the present invention which are produced by thermal decomposition of volatile compounds of metals or metalloids in the vapour state by means of oxidising or hydrolysing agents, if desired in the presence of a gaseous or v'aporous diluent or combustible gases. This can be seen from the following comparative experiments:

A mixture of 3 parts of pulverulent polymethacrylic acid methyl ester and 1 part of monomeric methacrylic acid methyl ester was mixed with 0.01% by weight of fillers, and the polymerisation was completed by heating for half'an hour to 100 C. The Brinell hardness of a moulded body thus obtained was determined with a 5 'mm. ball, a pressure of 62.5 kgs. per square cm. and a pressureduration of 30 seconds. The same experiment was repeated with no fillers at all and the Brinell hardi'ness was determined in the same way. In the latter case, i. e., without any fillers at all, a Brinell hardness or l3.3 was found. When using finely divided colloidal silica, which had been obtained by hydrolysing silicon tetrachloride with liquid water, a Brinell hardness of 14.4 was found, whilst on using a silica aerogel according to the invention a Brinell hardness of 18.0 was observed.

When the aerogels are used in the production of moulded bodies from natural or synthetic rubber or rubher-like substances or mixtures thereof the moulded bodies show excellent properties. Their properties are equal to and frequently exceed those of moulded bodies produced from rubber with the best American types of carbon black. The aerogels, which are obtained by thermal decomposition of vaporous metal or metalloid compounds in the vapour state, have even surpassed the excellent German carbon black in many respects, especially as re- "gards elasticity, impact-resistance, fatigue and extension of the moulded bodies produced with the aid thereof.

The use of the fillers of the invention, especially of very finely divided silica produced in the aerosol condition and collected as the aerogel, which is colourless, makes it possible to produce with advantage tread mixtures for motor tires and bicycle tires which are transparent or coloured as desired. These tire mixtures with a very low degree of filling with particularly finely divided aerogels, are not only equal to mixtures filled with highly active gas carbon black but surpass the latter as regards tensile strength and impact-resistance. Tires produced with such aerogels have the advantage, that, because of their low modulus value and related elasticity, they not only have better running properties as regards anti-skid action, braking power and the like, but also exhibit a much smaller evolution of heat and therefore have a greater resistance to wear than conventional tires produced with carbon black. In the same'way considerable advantages are obtained in many uses of natural and synthetic rubber, for example for the production of rubber shoe soles and objects of all kinds.

If desired theaerogels can be employed in combination with other fillers, known per se, such for example as carbon black, aluminum oxide and the like.

It is already known to use as rubber fillers oxides of metals such as are produced by the reaction of volatile metals with oxidising agents in the vapour state. The present invention however is concerned with filling rubberor-rubber-like material with aerogels produced by decomposition of volatile metal-or nietalloid compounds.

The known preparations made by vaporising and then oxidising metals have aparticle size which lies in part above 1 micron and can therefore not be used at all as fillers for rubber or rubber-like substances within the scope of the present invention. "If they are so used, the results are at any rate much worse than those obtained with the oxides to be used according to the present invention which have been produced from volatile metal or metalloid compounds and which have an elementary particle size ranging for example from 0.01 micron down to 0.005 micron. The smaller the particle size, down to a certain value, the better is the activity of the fillers.

The quantity of aerogels to be added according to the invention can be varied within wide limits. The aerogels can be incorporated during the production of rubber or rubber-like moulded bodies in the sam'e way as is usual when incorporating active carbon black. As the oxides employed according to the invention have a higher activity, a considerable smaller quantity of the fillers may be used for natural or synthetic rubber or rubber-like substances than with carbon black used 'as th'e'filler. In many cases 20 parts of the aerogel per 100 parts of rubber are suificient. The filler can be incorporatedin the usual way with addition of known assistants, such-for example as sulphur accelerators, zinc oxide and stearic acid. The incorporation can be carried out according to the process generally usual for tread'mixtures containing carbon black. In many cases, for example when using silicon dioxide aerogel, it has proved advantageous to make the proportion of accelerators and sulphur somewhat higher than is usual when using carbon black mix, tures.

The quantity'of aerogels to be incorporated with the synthetic resin like masses can likewise be varied within wide limits. In general additions of less than 20% of the total mass are sufiicient; in many cases it is desirable to make the additions considerably smaller, for

example 5 to 1% or lower.

Example 1 The effect of a silica according to the invention which is incorporated in natural rubber was determined by an examination of the mechanical properties of a vulcanized mixture, filled (a) with 50 parts by weight of silica and (b) with 50 parts by weight of carbon black. The rubber mixtures had the following composition:

Smoked sheet: silica. carbon black. zinc oxide PBN (phenyl beta naphthol) pinetar OIL The determination of the mechanical properties of the vulcanizates (cure time 40 min.) yielded for the various mixtures the following values:

The effect of oxide aerogels according to the 'inventioti was determined also in a synthetic rubber 60:40 poly isobutyl'styren'e c'o-polymer (Polysai' Butyl300") where- 5 by the following mixtureswere employed, filled'with (o) and with carbon black (I t 6f name Polysar Krylene, a 60:40 butadiene-s tyre necopoly; mer) was filled with the following mixtures:

( v Q (h). 6 v i Polysar Krylene 100 100 YolysarButy1300..-;--i.. 100 V 100 silica- 50- silica 50 carbon black- 50 carbon black. 150 stearic vi 2 2 I aflin 2 2 cumaron r in 7.5 7:5

5 gylcoL- 4 ,4 3 3 zinc oxide 5 5 nccelerator. V 2.9 1.2 accelerator 5 1 uiimv 3.0 2.0 suiiura 2.4

determination of the mechanical properties tafterva The determination of the mechanical properties yielded cure time of 50 min. yielded the following values: 1 the following values: a a a -i 1' tensile modulus tear resist- Shore Tensile tear-re=lst- Mixture strength, 300, ance frome. hardness Mixture strength, once from Shore kg /cm kgjcm, nick,kg /em,.

kgJem. 'anick, hardness I I V '1 .kgJcm. p v

I e as a a (0) mo 28 7'4 (b) 179 23.11 as v V ExampleS 4 i r l 3 This example serves as a comparative test between a l d 1 v. t f mixture which is normally filled with carbon-black- (a) b t In? 3 i gi p0 zz f and a mixture whereby the carbon black is partly sub'sti wias$g:c:: tg t kt2:fi e; o; $3 ig 3322) i 'tuted by a silica according to the invention (b); The l t mixtures had the followin com osition: bon black (m xture 12). The mixtures hadthe follow ng g p com osit'ion':

(b) Smoked Sheets 100' 160 carbon black S 108.

"7 "I "I" stearic avid 2 t 2 when blecke i iiii fia'reassures; i i 0.5 0.5 mm Y P gig: oxide. lg g r ator 0 6 1 6 enzy e er V accelerator 2.8 1.0 Sulfur" sulfur. I v 3 1.5 I H n. 4 p p 40 The determination of the mechanical properties ofthe The, determination of the mechanicalproperties; yielded vulcanizates (varying time of cure at a temperature of the 'following 'valuesz' 1 e v 140 C.) yielded the following values; I, .Time of Strength, Elong. at Mod.300, Elas- Shore Tearresist. Abrasion Mixture cure, kgJcm. break, kg./cm. ticity, hardfrom anick, (DVM),

min. percent percent ness kgJcm. mm.

20 269 606 90 41 33.8 v 40 287 582 110 43 64 28.0 (a) 60 282 570 113 41 65 24.2 271 551 111 40 65 26. 5 100 285 570 114 40 64 19. 7 20 297 631 47 59 32. a 40 300 619 46 60 26.5 (b) 60 288 611 90 47 59 24. 5 so 281 604 88 46 59 23.8 285 624 82 45 59 26. 1

Example 6 tensile tear resist- Mmm Strength, modulus mm from Show The cxample shows the influence of silica and titanium kgJcm. 300,kg./ern. a nick, hardness dioxide respectively, both substances pyrogemcally produced as aerogels, when used as filling agents in poly- 60 vinylchloride. As a softening agent dioctyl phthalate is {3: gag g 2% simultaneously incorporated in varying quantities together with the aforementioned oxides. Mixtures with various contents of softenin a cuts and an addition of 20 arts Example 4 g g p by weight of silica or titanium dioxide respectively,

Similar to the foregoing example a cold rubber (trade 5 yielded the following values:

Ike-data show that the fillers according to the invention are clearly superior to other filling-agents as, for instance, such essential properties of the polyvinylchloride as, for instance, the tensile strength and above all the tear resistance is highly improved.

Should special properties, for instance, a Shore hardness of 95 be obtained inf the'se mixtures, the content of the softening agent may-be increased in the mixture without impairing the tensile strength, if the pyrogenically produced oxides according to theinvention are simultaneously used as fillers as shown in the comparative test below. In order to obtain a Shore hardness of 95 the following mixtures are needed:

v Mixture tensile elongation strength at break 75 PVC, softening agent 225 225 Y or 65 PVC, softening agent and 20% Bio; 220 320 20 Example 7 7 Example 8 In foils made of polyethylene (strength 0.5 mm.) the tensile strength at break and the elongation were determined. To several mixtures polyisobutylene was also added. The determination yielded the following values whereby the first figure represents the tensile strength at break or the elongation respectively in the longitudinal direction, i. e. in the roller direction, whilst the second figure represents the tensile strength at break or elongation in cross-direction to the roller.

Mixture Tensile Elongation,

strength, percent polyethylene polylsosillclumkg./mm.

. .butylene dioxide I claim:

1. A moulding composition comprising a high molecular weight polymeric material selected from the group consisting of polyvinyl chloride and polyethylene having dispersed therein up to and including 20% by weight of a finely divided Q i Oxi e ha in a p t e s z of ss. than 50 my selected from, the group consisting of silica, aluminum oxide and titanium dioxide produced by the vapor phase decomposition of a corresponding volatile compound by an agent selected from the group consisting of oxygen and water vapor.

2. A moulding composition comprising polyethylene having dispersed th r in up o and in luding 20% by weight of a finely divided solid oxide having a particle size of less than 50 m selected from the group consisting of ili alu inum wide an it n um dioxide P odu by the p r ha deqqmneti on' f a o p ndi volatile compound by an agent selected vfrom the group consisting of oxygen and water vapor.

3. A moulding composition comprising polyvinyl chl ride having d spersed. therein up o and in luding 20% by weight of a finely divided solid oxide having a particlesize of less than 50 my selected from the group consisting of silica, aluminum oxide and titanium dioxide produced by the vapor phase decomposition of a corresponding volatile compound by an agent selected from the group consisting of oxygen and water vapor.

References Cited in the file of this patent UNITED STATES PATENTS 2,428,252 Von Stroh a Sept. 30, 1947 2,453,052 Van Etten Nov. 2, 19.48 2,578,605 Sears et al Dec. 11, 1951 

